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SubjectRe: [PATCH mm v3 30/38] kasan, vmalloc: don't tag executable vmalloc allocations
On Mon, Dec 13, 2021 at 10:54 PM <andrey.konovalov@linux.dev> wrote:
>

[...]

> @@ -3133,10 +3133,14 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align,
> * (except for the should_skip_init() check) to make sure that memory
> * is initialized under the same conditions regardless of the enabled
> * KASAN mode.
> + * Tag-based KASAN modes only assign tags to non-executable
> + * allocations, see __kasan_unpoison_vmalloc().
> */
> kasan_flags = KASAN_VMALLOC_VM_ALLOC;
> if (!want_init_on_free() && want_init_on_alloc(gfp_mask))
> kasan_flags |= KASAN_VMALLOC_INIT;
> + if (pgprot_val(prot) == pgprot_val(pgprot_nx(prot)))

Can simply compare with PAGE_KERNEL here to match the check in
arch_vmalloc_pgprot_modify(). Will do in v4.

> + kasan_flags |= KASAN_VMALLOC_NOEXEC;
> addr = kasan_unpoison_vmalloc(addr, real_size, kasan_flags);
>
> /*
> @@ -3844,7 +3848,7 @@ struct vm_struct **pcpu_get_vm_areas(const unsigned long *offsets,
> for (area = 0; area < nr_vms; area++)
> vms[area]->addr = kasan_unpoison_vmalloc(vms[area]->addr,
> vms[area]->size,
> - KASAN_VMALLOC_NONE);
> + KASAN_VMALLOC_NOEXEC);
>
> kfree(vas);
> return vms;
> --
> 2.25.1
>

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